wagner



Oct. 15, 1929. H, W NER 1,732,198

AUTOMATIC SKIP CONTROLLING MECHANISM Filed Feb. 1, 1928 2 Sheets-Sheet 1 Oct. 15, 1929.

c. H. ,WAGNER AUTOMATIC SKIP bQNTROLLING MECHANISM 2 Sheets-Sheet 2 Filed Feb.-l, 1928 mbo'znu Patented Get. 15 1929 UNITED STATES PATENT OFFICE cnnnnns 1r. WAGNER, or WASHINGTON, nrs'rn or or ennui/min, assrenon T KOEHRING COMPANY, OF MILWAUKEE, Wiscons n, A CORPORATION U OMATIC SKI C N BQLIJNG MECHANISM Application fil ed February 1, 1328. Serial No. 251,198,

The present day construction of concrete roads usually involves the employment of a concrete mixer of the so-called paving machine type. One of these pavers comprises 5 generally, a mixingdrum, a skip for charging aggregates in their unmixed condition into the drum, discharging means for taking the mixed aggregates from the drum, and some form of distributing means such as the well known boom and bucket construction. A paver also usually includes a power plant that not only drives the various mechanisms making up the paver, but also provides tractive power ior moving the machine along the sub-grade.

Modern developments in the paving machine of this character have been directed to the elimination of manual control over the operation oi the various parts of the paver to the greatest feasible extent, and in accordance with this tendency, I propose by this invention to provide means for automatically controlling the operation of a skip during certain steps in the cycle of operationxof the paving machine.

In the conventional operation of the machine, the ship is hoisted to an upraised charging position in which the aggregates in the skip pass intothe mixing drum, which action consumes a certain more or'less definite period of time. Carrying out the idea of the preceding paragraph more specifically, I provide mechanism for holding theskip in its upraised or charging position for a predetermined period of time sufficient in length to permit the aggregates in the skip to be completely charged into the mixing drum, and then automatically initiate the downward movement of the skip. This arrangement in.-

40 sures the complete discharge of the aggregates into the mixing drum with every batch without entailing any loss of time which might be engendered by maintaining the skip in. its charging position longer than is necessary, as is often the case under conditions of manual controlling. In the mosti'easible efficient operation of a mixer, the mixing period of a batch in a drum is so ins tel-related with the cycle of operation of the skip that the elimination of any delays as,-

sumes paramount importance. Under conditions of efficient operation, a skip should be lowered, loaded, and hoisted into its charging position, all in the period of time consumed in the mixing of one batch in the The automatic control mechanism provided by this invention, is also adapted for cooperation with the now known means tor automatically initiating upward movement of the skip.

My novel control mechanism comprises generally a braking means associated with the skip hoist drum as previously mentioned, that is automatically applied when the skip reaches its limit of upward movement to hold the latter in this charging position. Additional mechanism is incorporated with the braking means aforesaid for discontinuing the braking action of the same after the elapse of a certain predetermined length of time, which is the period consumed by the passage of the aggregates from the skip into the mixing drum.

Another highly important object of the invention is to provide governing means for controlling the rate of speed of the skip in its downward movement. In providing an appropriate mechanism for carrying out this object, I associate supplemental braking means with the controlling mechanism aforesaid, together. with the governing instrumentalitiestor applying the former so as to pre vent the rate of speed of the skip in its descent from exceeding a certain safe limit. Inasmuch as gravity action supplies the actuating impulse for the downward travel of the skip, and bearing in mind the ponderance and heavy weight of this element, it is of essential importance to Stop the skip from attaining a speed beyond the b nds of af operation. Otherwise, large damage to property and possibly life, would result.

Other and more d tai ed objects and dvantages will in part become apparent, and in parts in section.

Figure 3 is a side view of the dash pot and associated mechanism, the dash pot being shown in section, the remainder of the structure in elevation.

Figure 4 is a longitudinal sectional View of the brake drum taken approximately on the line 1-t of Figure 2.

Figure 5 is an enlarged. detail illustration somewhat fragmental, of a portion of the dash pot.

Vi hile a preferred embodiment of the invention is herein set forth, it is to be understood that I am not to be limited to the exact construction illustrated and described, because various modifications of these details may be provided in put-ting the invention in practice within the purview of the appended claims.

The invention herein disclosed and claimed, is disclosed but disclaimed in the copending application of John F. Robb, filed August 17th, 1926, Serial No. 129,785, on which Patent No. 1,660,301 issued on February 21st, 1928, and I have shown a specific embodiment of the invention as it is adapted for cooperation with the various controlling mechanisms of the noted copending application.

The parts of a paving machine with which the mechanisms constituting niy invention are particularly related, are a mixing drum designated in the drawings by the reference character A, a loading skip indicated at B, and a water tank fragmentarily shown at C. The paver also includes a batchmeter D that functions to control the mixing period of a batch in the drums in certain types of paving machine, and a suitable power plant E which drives a main drive shaft 1, from which power is taken to operate the component parts of the mixer, and for the purpose of this invention more particularly a skip hoisting drum 3.

The skip B is mounted on the frame work of the paver in the conventional manner as clearly shown in the copending application referred to, as are various other operating instrumentalities to be hereinafter more fully described. 7

The skip is hoisted through the mediur'n'of a winding drum mechanism (not shown) that is driven by a cable 2 which is taken up on the skip hoisting drum 3. Intermediate the drive shaft 1 and the hoisting drum 3, there is located a clutch mechanism which may be of any well-known type. i In the present instance this clutch is shown as a multiple disc clutch and is designated by the reference character 1. The clutch 1 is operable to provide a driving connection between the shaft 1 and hoisting drum 3, or establish an idling relation between these parts. An operating lever 5 is pivotally mounted on the frame work at 6 and is connected at 7 to operate the clutch mechanism. This lever 5has a hand grip at one endwhich may be availed of when it is desired to discontinue the automatic operation of the machine, while extending beyond the pivot 6 is a portion that is connected with certain linked members to be hereinafter more fully set out. 7

Suitably associated with the skip B is a knock out roller 8 that is adapted to abut one end of a lever 9 which is pivoted at 10 to a the frame work of the paving machine. The other end of the lever 9 is connected by a pin and slot connection with a connecting link 11. The link 11 has a similar pin and slot connection at its other end, by which it is connected with an operating arm 12 of the batchmeter D. This batchmeter is of the particular construction clearly illustrated and described in the copending application of Robb hereinbefore referred to. This construction is such that upon a pull being imparted to the arm12, a downward motion is given to a second arm 13 projecting from batchmeter D. A connecting rod 14 is pivotally connected at one end to the arm 13 and at the other end to one arm of a bell crank 15 which is pivoted to the frame work at 16. The other arm of the bell crank 15'is connected by a linked member 17 to the operating lever 5 through the medium of an appropriate pin and slot connection as shown at 18. mechanism functions to knock out clutch 1 upon the skip B reaching its charging position to discontinue upward travel of the latter. 7

' The connecting rod 14: carries in the proximity of its lower end an actuating roller 19 which on downward movement of the rod, engages, one end of a lever 20 to impart rocking motion thereto. The lever 20 is pivotally mounted on appropriate support and has an end 21 projecting beyond the pivotal point in an opposite direction from the end sometimes engaged by the roller 19. The downward movement of the roller 19 causes upward motion of the lever end 21, thereby causing the latter to abut one end of a pin The foregolng 22. Pin 22 extends upwardly into a dash pot 23 wherein it is connected with a piston 24, the detail construction of which will be later described. A collar surroundsthe pin 22' and is held in position intermediate dash pot 23 and lever arm 21 by coil springs 26. A brake lever 27 has one end aflixed to the collar 25 while its other end is in pivotal connection with one extremity of a brake band 28. Adjacent the brake band 28, the lever 27 is pivoted at 29 to a link 30 which is in turn pivotally mounted at 31 to an appropriate support 32. The brake band 28 is somewhat circular in formation and has one end connected to the lever 27 as previously mentioned, while its other extremity is fastened to the support at 32. The inner surface of the band 23 is provided with the requisite brake lining 33. I

Referring more particularly to Figure 4, the skip hoist drum 3 has integral therewith at one end a brake drum 34 which is surrounded by the brake band 28, and is gripped thereby when braking action is to be applied to the drum for the purpose of preventing its rotation.

T he outer end of the drum 34 is partially closed by the flange 35 which however leaves a recess of a somewhat smaller diameter than the drum itself. A secondbrake drum 36 is freely mounted on the drive shaft 1, and has at its outer or free edge, a peripheral flange comprising a series of ratchet teeth 37, this being clearly brought out in Figure 2. A bell crank latch 38 is pivotally mounted at 39 to an appropriate support on the frame work of the machine, and has at the extremity of one arm a weight 40 for keeping the large member in engagement with. the ratchet on the drum 36. It will be apparent that the structure permits the free and unrestricted rotation of the skip hoist drum in one direction but in cooperation with certain braking means to be hereinafter described, restricts the speed of rotation of the drum in the opposite direction, which for the object of this invention will be the direction of rotation of the drum entailed by the lowering of the skip.

Preferably integral with the skip hoist drum and projecting therefrom co-axial with the drums and 38, is a hub member 41 havradilly projecting arms 42, two in number, arranged diammetrically oppositeone another. Pivoted to the extremities of the arms 42 are linked members 43 which are pivoted at their other ends to toggles 44. llogglcs 44'have their free ends pivotally connected to the extremities of a sectional brake band 45 lined with appropriate brake lining 46. Governing arms inthe form of hell cranks andof any suitable number are pivotally mounted on the hub 41, designated b the reference character 47 In the present instance three of these governing members are shown or any desired number may be availed of. The ends of one arm 01' each of the governors are weighted to afford proper the form of coil springs 49 connect the weighted arm of each governing member with an adjacent governing member near its pivotal mounting. This arrangement tends to maintain thegovernors in their collapsed or more central position from which they depart only when suflicient centrifugal force has been caused by the rotation of the skip hoist drum to throw them outwardly. Linked members 50 connect the toggles at their pivotal point with the ring 48 at substantially opposite points. Upon rotation of the skip hoist drum, the centrifugal force generated thereby causes the weighted arms of the governors 47 to move outward, which motion, due to their bell crank construction and pivotal mounting on the hub 42, causes a rotation of the ring 48. This circular movement in turn causes linked members 50 to operate the toggles 44 by imparting aspread action thereto which applies the brake band 45 to the inner surface of the brake drum 36 whereby the drum 36 is given a tendency to rotate with skip hoist drum. However, if the former is held against rotation by the latch 38, this tendency will cause a restriction or decreasing of the speed of rotation of the skip hoisting drum 3. It is to be remembered that this action takes place only upon rotation of the drum 3 in the direction caused by the lowering of the skip, because in the upward movement of the skip the drum is turned so that its rotation is in no way effected bythe drum 36 due to the arrangement of the ratchet and latch hereinbefore described.

Referring now to Figures 3 and 5 we come to the particular construction of the dash pot 23. .This dash pot comprises a cylindrical casing 51 that is closed at both ends. The lower end has an opening through which extends a pin 22 which is aiii xed to the piston 24 as previously mentioned. Means of communication between the upper and lower portions of the dash pot is effected by the employment of a tubular member 52, the bore of which may be .adjustably restricted at some convenient point by a valve 53 of any suitable construction. The piston 24 may include any desired one way valve construction-that will. readily permit fluid to flow therethrough, I have shown one such arrangement as consisting of openings 54 extending through the piston and which are closed by a flap member 55 positively held inposition by suitable connection with the pin 22. A fluid tight relation between the piston 24 and casing 51 may be afforded by the use of packing members 56.

The casing 23 is substantially filled with some fluid such as heavy oil of proper viscosity to effect the desired operation of the dash pot which is substantially as follows Upon upward movement being imparted to the pin 22 the piston 24 is forced upwardly, the fluid passing through the openings 54, which passage is permitted by the flap 55. Possibly some small portion of the fluid would pass around through the tube 52. Upon the arrival of the piston 24 at the top of the casing and any impulses causing upward movement of the pin 22 being discontinued, the springs 26 will by their expanding action cause the pin 22 accompanied by the piston 24 to recede to their normal positions. However, this motion will be opposed by the fluid in the dash pot which cannot flow back through the openings 54 due to the one way valve con struction. The only path which the fluid may take is that through the tube 52 inasmuch as the bore thereof is restricted to a certain extent. A certain predetermined length of time which may be varied through proper operation of the valve 53 Will be consumed by the fluid in passing from the position in the dash pot beneath the piston 24 to that thereabove, which action must take place in order for the piston 24 to reassume its position adjacent to the bottom of the casing. The eflect of the operation of this dash pot is to maintain the application of the brake band 22 for a certain predetermined period of time, after which it is discontinued.

The operation of the controlling mechanism herein described is substantially as follows:-

Upward movement of the skip 3 is initiated by operation of the lever 5, either manual or automatic, to set up a driving relation between the drive shaft 1 and the skip hoist drum 8 through the medium of the clutch mechanism 4. The winding of the cable 2 on the drum raises the skip. When the skip reaches its uppermost position, the roller 8 engages one end of the bell crank 9 and operates the latter to exert a pull on the link 11. This pulling action operates batchmeter D in a manner completely described in the copending application of Robb, to not only set the batchmeter to determine the mixing period of the batch in the drum, but to cause downward movement of the rod 14. This last named motion does two things, through the bell crank 15 and link 17 it operates the lever 5 to knock out the clutch 4 and thereby discontinue hoisting action of the drum. At the same time the actuating roller 19 engages lever arm 20 which eilects an abutment of the other lever arm 21 with the pin 22 causing the latter to move upwardly. This upward motion moves the collar 25 to apply the brake 22 to positively prevent rotation of the skip hoist drum 3. At the same time the dash pot 24 is set so that the brake is held applied for a certain predetermined length of time which may be varied by adjusting the control valve 53. The piston 24 slowly'moves downward to its lowermost position, whereby the brake 22 is released and the downward movement of the skip is initiated, the skip thus having been held in its upraised condition just long enough to discharge the ag gregates contained therein into the mixing drum A. I

The descent of the skip necessarily entails an unwinding of the cable 2' from the skip hoist drum 3, thereby rotating the latter. Should the speedof the downward travel of the skip aproach a certain safe limit, the drum 3 wil be rotated sufliciently fast to produce centrifugal force necessary to cause the governing members 47 to fly outwardly, which action applies the brake band to decrease or restrict the speed of rotation of the skip hoist drum 3* and in turn, the descent of the skip B. In this manner the operation of the skip is eifected with the hi hest feasible degree of efiiciency and at alf times kept within sate bounds.

While in the present embodiment oi? the invention one particular type of governor is illustrated and described for the purpose of bringing out the invention in one specific form, it is to be clearly understood that it is to be within the purview of my invention to avail of any means for controlling the descent of the skip after it has reached a position in which the aggregates are charged into the mixing drum.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is ,1.In mixing mechanism of the class described, in combination, with a skip, a means for automatically controlling the operation of the skip upon its reaching a charging position, means for releasing said control means, and means for automatically retarding the lowering of the skip throughout said lowering movement.

2. In mixing apparatus of the class described, in combination, with a skip, a skip hoisting drum, means for discontinuing hoisting of the skip by the drum, of means associated with the drum and operable upon rotation of the drum in only one direction for automatically controlling the downward travel of the skip throughout its downward movement.

8. Mixing apparatus of the class described, comprising, a mixing element, charging means for depositing aggregates in the mixing element, means for elevating the charging means into a charging position, and brake means associated with the elevating means for maintaining the charging means in its charging position for a predetermined length of time and then automatically initiating its downward movement, together with control means automatically acting on the brake to control the descent of the charging means throughout the descending movement.

4:. Mixing apparatus of the class described, comprising, in combination, a mixing element, means for charging aggregates into the mixing elements adapted to assume loading and charging positions, and means for automatically releasing and retarding the movement of the charging means from its charging to loading position.

5. Mixing apparatus of the class described, comprising, in combination, a mixing element, a skip for charging aggregates into the mixer, means for elevating the skip into charging position, and means for controlling the downward movement of the skip, said means being brought into operation by variations in the speed of downward travel of the skip.

6. Mixing mechanism of the class described, comprising, in combination, a mixing drum, a charging device for loading aggregates into the drum, a hoisting drum for elevating the charging means into charging position, and means operable incident to re verse rotation of the hoisting drum for controlling the downward movement of the skip.

7. In concrete mixing apparatus of the class described, comprising, in combination, a mixing element, a skip, means for raising the skip in a charging position, means associated with the last named means for maintaining the skip in its charging position for a predetermined length of time, and then automatically initiating its downward movement, and centrifugal governing means for controlling the downward movement of the ski 8 In mixing apparatus of the class described, comprising, in combination, a mixing element, means for charging aggregates into the mixing element, means brought into operation by the charging means reaching its charging position, for maintaining the said charging means in the said position for a predetermined length of time and then initiating its downward travel, and means for controlling the downward movement of the skip operable incident to variations in the speed of the downward travel.

In testimony whereof I afiix my signature.

CHARLES H. WAGNER. 

